Submitted to: Photochemistry and Photobiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2002
Publication Date: 12/1/2002
Citation: Kaanumalle, L.S., Shailaja, J., Robbins, R.J., Ramamurthy, V. 2002. Cation controlled singlet oxygen mediated oxidation of olefins within zeolites. Photochemistry and Photobiology. 153:55-65. Interpretive Summary: An oxidation of alkenes reaction gives different products when it is carried out inside zeolite supercages versus when carried out in solution. Thus allowing for control of product formation that had been previously not possible. Restricted movement inside the supercages leads to the preference of one product over another. Computer based calculations help explain that a positive ion found inside the zeolite supercage holds the alkene in a certain position when singlet oxygen approaches during the course of the reaction.
Technical Abstract: Oxidation of trialkyl olefins has been performed within zeolites employing thionin as the singlet oxygen sensitizer. Unusual selectivity in favor of secondary hydroperoxides is observed within zeolites. In light of the fact that in solution such a selectivity is never observed the selectivity reported here is of great sinificance. Based on computational results the observed selectivity is attributed to conformation control of the reactant olefins by cations present in zeolites. Cation-pi interaction seems to control the behavior of the olefins towards singlet oxygen within zeolites.